This month the Addison Street arts corridor was overtaken by gaggles of girls, and their mothers, and a small clutch of guys who — and I'm not being facetious — don't mind getting in touch with their "inner girl." The draw? Eve Ensler's Emotional Creature, the latest from American pop culture's most famous vagina monologist, now enjoying its world premiere at Berkeley Repertory Theatre. Ensler based the new play on a book of fictional stories and soliloquies, inspired by interviews she conducted with young women from all parts of the world. Themes ranged from the banal — popularity, envy, vanity — to more sobering concerns — rape, sex trafficking, female genital mutilation — but the playwright regarded them all with the same earnest vehemence she'd bestow on any feminist issue. She ultimately transformed the book into a play, in which a multiracial, all-girl ensemble presents a series of first-person testimonials, all penned by Ensler but persuasively rendered by the performers. It's captivating, even if the execution far outweighs the script.

The problem with Ensler is that she views every artistic forum as a soapbox, so no matter how impassioned or entertaining or electrifying her material, that evangelistic impulse will always shine through. That was a defining factor in The Vagina Monologues, which is all about teaching women — well, society — not to fear their genitalia, and which eventually spawned an activist movement called V-Day, through which Ensler and her ilk attempted to curb violence against women. And Emotional Creature falls in the same vein. It's a mix of drama and comedy, much of it accompanied by dizzying video montages or explosive song-and-dance numbers, all intended to shore up sentiment and create an atmosphere of female empowerment. But underneath that show-biz veneer you can always sense the 59-year-old author, issuing directives and whacking us on the head with her political messages.

That's apparent from the play's preamble, actually a list of statistics projected on video screens that line the stage. They provide a rather dismal account of the calamities facing young women: the death rate from anorexia, the recent uptick in plastic surgery for teens (mostly boob jobs and rhinoplasties), the shockingly high frequency of rape and domestic violence. Ensler throws in a few more stats for good measure, even if they serve more to indict women than defend them — when asked to name their hobbies, she said, 80 percent of teenage girls named "shopping" as number one. (Ketchum Global Research Network drummed up the same stat in a 2010 poll, although, granted, "reading" was a close number two.) Just maddening.

That, and the giant clip-art pictures of cupcakes, sets the tone for Ensler's ninety-minute play, which was directed by Jo Bonney and which features a score by Charl-Johan Lingenfelder. It starts off light: The cast members play a game of "Would You Rather ...?" to introduce the themes of their play (e.g., "Would you rather be the most beautiful, or the most brilliant?"), and follow it up with a skit about social cliques in high school, narrated by actor Molly Carden. The first few vignettes all center on issues that might resonate for an American audience: loyalty and gamesmanship; contraception; societal obsessions with beauty; the pressure to be thin. They're depicted with remarkable verisimilitude by actors who can accurately mimic the speech patterns of real teenage girls, and who occasionally veer into poetry: "Pretty girls are just swimming like goldfish in a bowl," Sade Namei muses, in a monologue about a forced nose job.

About a third of the way through, it gets grim, first with Carden's depiction of a sex slave from Eastern Europe (and a single eye projected in the background), then with Joaquina Kalukango's recounting of rape and torture in the Democratic Republic of Congo. These parts are extremely moving — mostly because of the way in which each actor inhabits her role — but they have the tenor of a political speech, rather than a play. And that's where the voice of Ensler starts creeping in.

"When I was growing up, I was told that I was too hysterical, that I was too alive, that I was too dramatic," she recalled during a recent phone interview, when asked to explain the etiology of her term "emotional creature." Since then, she's been intent on letting her voice fill a room, occasionally at the expense of her characters' voices — or of the narrative cohesion in her plays. Emotional Creature is terrific as a screed: It's inspiring, the music is giddy and propulsive, and Myung Hee Cho's set and Shawn Sagady's video work provide a vibrant subtext for every scene. If that was Ensler's intent, then by all means, she's succeeded. But if she wants to make a great play, she'll eventually have to stop exhorting and homilizing.